The present invention relates to a vane pump which is one of rotary pumps used for various kinds of apparatuses such as a supercharger of an engine, a compressor of a freezing cycle, and the like.
A vane pump schematically shown in FIG. 12 has been heretofore widely known.
In FIG. 12, reference numeral 101 designates a housing; 102, a rotor inserted eccentrically into an inner peripheral space of the housing 101 and rotatably supported by a rotational shaft 103; 105a, 105b and 105c, plate-like vanes disposed radially retractably from vane grooves 104a, 104b and 104c equally spaced apart so as to peripherally divide the outer peripheral side of the rotor 102 into three sections. When the rotor 102 is rotated in the direction as indicated by the arrow X by the rotational shaft 103, the vanes 105a, 105b and 105c are moved out in the direction of the outside diameter by the centrifugal force, and the end edges thereof rotate while slidably contacting the inner peripheral surface of the housing 101. Since the rotor 102 is eccentric with respect to the housing 101 as previously mentioned, as such rotation occurs, volumes of working spaces 106a, 106b and 106c defined by the housing 101, the rotor 102 and the vanes 105a, 105b and 105c are repeatedly enlarged and contracted to allow a fluid taken in from an intake port 107 to be discharged out of an outlet port 108.
However, the above-described conventional vane pump has problems that since the vanes slidably move along the inner peripheral surface of the housing at high speeds, the efficiency of the volume caused by the great power loss due to the sliding resistance and by the generation of high sliding heat unavoidably deteriorates; the vanes materially become worn; and the vanes are expanded due to the generation of sliding heat to produce a galling with the inner side surfaces of both end walls of the housing, and the like.
In view of these problems as noted above, it is an object of the present invention to enhance the efficiency of such a pump and enhance the durability thereof.